Clutch for induction-motors.



N0. 70$,ll7. Patented Aug. 5, 902.

A. SCHWARTZ. I CLUTCH FOR INDUCTION MOTORS.

(Application filed Oct. 28, 1901.)

(No Model.)

M2 33 ,gd

NITED STATES PATENT OFFicnf ALFRED'SOHWARTZ, OF MUNICH, GERMANY,ASSIGNOR TO HELIOS ELEC- TRIOITAETS-AKTIENGF.SELLSOHAFT, OFOOLOGNETEHRENFELD, GER- MANY.

CLUTCH FOR INDUCTION-MOTORS.

SPECIFICATION forming part of Letters Patent No. 706,117, dated August5, 1902.

To all whom, it may concern.-

Be it known that I, ALFRED SCHWARTZ, a subject of the German Emperor,and a resident of Munich, Germany, have invented cert-ainnewandusefulImprovementsinOlutches for Induction-Motors, of which thefollowing is a specification, the present application be-- ing adivision of my prior application, Serial No. 51,734, filed March18,1901. I

My present invention relates to an automatic clutch or coupling by theuse of which (in connection with my method of starting induction-motors)the starting-current in mo tors for single-phased or multiphasedcurrents may be greatly reduced, so that larger types of motors may beconstructed with short-circuit armatures than has been heretoforepossible with respect to the high-starting current. Moreover,theinvention enables special devices for displacing the phases in theauxiliary phase employed in asynchronic single-phased motors to beomitted. In many cases the auxiliary phase may be dispensed with. g

The principle involved by the invention is as follows: The shaft of thearmature is extended on either side and journaled so that the armaturemay be easily shifted in axial directions. When the armature having, forinstance, a short-circuit winding is located in its static field andwhen the latter is inserted into the circuit, the armature will bepushed axially out from the field, and in this position, in which it ispartially out of the field, it will be started without charge after aslight rotation is imparted to it either by hand or otherwise, saidarmature making its normal number of revolutions after a short time.When the same rotates at its normal speed, just at the moment ofsynchronism it is again pulled into the field and then coupled by meansof a clutch, also operated at this'moment by the axial movement of theshaft. By reason of said clutch the motor-for instance, a single-phasedmotor-will be coupled to its charge only after the synchronism isreached. Experiments have proved that the starting of the motor undercharge in this manner is efiected in a few seconds.

The invention will now be clearly described lJivided and thisapplication filed October 28, 1901, Serial (No model.) W

with reference to the accompanying drawings.

Figure 1 is a longitudinal section of the clutch with the pulley R, theclutch-disk S, and the disengaging device T. Fig. 2'is a rear elevationof the clutch-disk S, and Fig. 3 is a front elevation of the disengagingdevice T. Fig. 4: shows the clutch in combination with a motor,a'nd Fig.5 shows a modified form of clutch.

By reason of the lateral shifting imparted to the armature of aninduction-motor at the moment it reaches the normal speed thecentrifugal clutch (shown in Fig. 1) will be en- The overlapping edge Nprevents the pulley from being moved to the right. The inner cylindricalwall O of the extended part of the pulley receives the engaging jaws B,guided in the perforated projections s of the'disk S and moved radiallytoward the shaft by the action of springs g. Eachof the jaws carries onone side a small roller X, which is located under the curved rim orretainer T when the motor does not run at the required speed. The disk Sis keyed on the shaft \V, while the retainer or rimT is adapted to slide1ongitudinally on the latter. The relative rotation between the diskSand the retainer or rim T is avoided by means of four bolts D, screwedin the part T and extending through holes 0 in the disk S. The free endsof said bolts are also provided with small rollers Y. Arranged between Tand the collar a, keyed on the shaft, is a coil-spring F, reinforcingthe tendency of the armature to move out from the field when the latteris inserted into the circuit.

So long as the speed of the motor is under the normal full speed theclutch-disk will be disengaged from the belt-pulley R by reason of theposition of the armature. Further. more, the jaws 13 cannot beinfluenced by the centrifugal force, as the spring F holds the curvedrim T over the rollers X; but when the full speed is obtained and whenthe armature pulls the shaft toward the left the jaws B will partiallyenter the hollow cylinder 0. At the same time the retainer or rim T ismoved in the same direction by the spring F, said disk being pushed backat the moment the small roller Y engages the wall K of the pulley,whereby the disk S enters alone the cylinder 0, as the rollers X are nowdis-' engaged from the retainer or rim T. Thus the jaws B are influencedby the centrifugal force, whereby av sudden coupling with radialpressure is produced.

When the motor is out out, the armature will be moved to the right outof the field and the centrifugal force of the jaws will be quicklydecreased, so that the springs may move the same toward the shaft andthat the rollers X may again be brought under the retainer T.

Fig. 5 of the accompanying drawings shows that the improved clutch mayalso be applied to a belt-pulley R, provided with projections U, wherebythe clutch acts as an ordinary clutch instead of a friction-clutch.

Having fully described my invention, what I claim, and desire to secureby Letters Patout, is-

1. In a clutch for induction-motors,the combination with a journal, of abelt-pulley moun ted on the journal and provided with an extendedcylindrical wall, an interior wall or partition in said pulley, a diskmounted to slide on the journal, radially-movable clutchj aws carried bysaid disk, rollers carried by and extending outwardly from said jaws,means adapted to engage said rollers for holding said jaws in theretracted position, and means for engagement with the interior wall ofthe pulley to release the retaining means whereby said jaws engage theextended cylindrical wall of the pulley, substantially as described.

2. In a device of the character described,- the combination with thejournal, of a belt pulley mounted thereon and provided with an interiorwall or partition, a disk mounted for longitudinal movement on saidjournal, radially-movable jaws carried by said disk, rollers carried bysaid jaws, a spring-pressed retainer mounted on said journal forengagement with the rollers to normally hold said jaws in the retractedposition and means for engagement with the interior wall or partition ofthe pulley to disengage the retainer from the pulleys, as and for thepurpose specified.

In testimony whereof I have hereunto set my hand in presence of twowitnesses.

ALFRED SCHWARTZ. \Vitnesses:

R. W. HIEBL, ELLUND NILsoN.

